Telephone-exchange system



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A. E. LUNDELL TELEPHONE EXCHANGE SYSTEM Fiied Nov. 8, 1920 8 Sheets-Sheet s V A/mw L ands/l.

May 20', 1924. 1,494,924

A. E. LUNDELL TELEPHONE EXCHANGE SYSTEM Filed Nov. 8-. 1920 8 Sheets-Sheet4 i 170/4 70/4- A/Wn Z nde/L May 20, 1924.

A E. LUNDELL v TELEPHONE EXCHANGE SYSTEM 8 Sheets- Sheet 5 Filed Nov. 8

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' A. E. LUNDELL I TELEPHOl ifl EXCHANGE SYSTEM May 20 1924. A. E. LUNDELL TELEPHONE axon/mes SIYSTEM Filed Nov. 8 1920 8 Sheets-Sheet 8 wsm Patented May 20, 1924.

ALBEN E. LUNDELL, on NEW'YORK, N. Y., ASSIGNOR'TO-WESTERN E ECTRIC come PANY, INCORPORATED, a, CORPORATION onN w 01m. I

TELEPHONE-EXCHANGE- SYSTEM.

ApplicationfiledNovember a, 1,920,- se i 422,553.]

To all whom it may concern; i

Be it known that: ILALBENI. E. LUNDELL, a citizen of the United States, residing at New York, in the county ofNew York and State of New. York, have invented certain new and useful Improvements in Telephone- Exchange Systems, of which the followingv is a full, cle-ar,.concise, and: exact description.

This invention relates to automatic telephone exchange systems, andmoreparticularly to systems in which aregistration of the designation of the Wanted line is accomplished; at a central oifice.

More specifically, the invention is an improvement on application Serial No. 393,- 377 filed July 1, 1920, by A. E.'Lu ndell and J. J Wynne, wherein is shown a method of transferring registrations from primary registering, devices to other registering devices which are subsequently utilized to control automatic switches which set up connections between calling and called subscribers.

It is the object of this invention to pro- 'vide an improved method of transferring a registration from one setof registers to another.

Features of; the invention are the use of an intermediate registering device which is positioned in accordance with; the position assumed by a set of primary registers, and the subsequent positioning of a set of secondary registers by means of impulses supplied from a common impulse generating device.

In the application above mentioned a,

large number of brushes were employed on the intermediate multi-position registering device. In accordance with the present invention, the. large number of brushes is eliminated and all of the registrationsmay be accomplished by means of impulsestransmitted through a single brush and its associated contacts. Thisresults in ahmarked saving in the cost of the apparatus. A larger and more complicated.impulse sending device is required, but since one impulse sending device is suflicient to serve an entire exchange, theadded cost of the impulse sending device is considerably over-balanced by the saving of the cost of the multi-position switches required.

An added featureof the invention is an arrangementwhereby the use of a single relay accompl shes the distribution of a plurality of a series of impulses to acontrolv wire Without the use of an auxiliary. distributing switch.

Other features .of the invention result from the arrangement of the controlling circuitsfor the multiposition intermediate register and the various register relays and.

' will be more clearly apparent from the detailed description which follows:

The invention has been showmapplied to a semi-mechanical system of-the type shown in the above mentioned. application by A. E. Lunde1l and. J. J. Wynne. It is, ho'w-v ever, obviously-capableof a wide range. of usageand is, therefore, not .to be limited to the specific embodiment shown.

In the drawing the variousfigures show somuch of a telephone exchange system as isnecessary to an understandingof the in vention. Fig. 1 shows a link circuit at. a cordlessoperators position and includes a district selector switch and controlling circuitsthereior. 2 shows a. link circuit to be used in associating an idle sender with the cord; circuit which has been taken for use. and includes the controlling circuits for a cord. finder switch and a sender selector switch. Fig. 3 shows a portion of the. control circuit .forsetting the sender register relays. Fig. 4. shows a set. of count-. ing relaysfor controllingthe operation of the. various selector switches of the system together with. a sequence switch to control the progress of operations in the sender.

Fig. .5 shows a group of register relays and a .class sequence switch and its circuits.v Figure 6 shows an. impulse generating device to be used in setting the register relays of Fig. 8 in accordance withthe position assumed by the multiposition switch of Fig, 7. Fig. 7 shows an operators key set together; with a multiposition switch which assumed a position in accordance with which keys have been depressed. In Fig. 8 are shownthe circuits of various register relays together with a controlling sequenceswitch' which not only controls the operation ofthe multipositionswitch of'F'ig. 7 but also controls the progress of impulse transmission in teni'will first be given order that the des more readily understood.

The operation of the system 1s substantially similar to that described in the above tailed description which follows may be mentioned application by A. E. Lundell and J. J. Wynne, and in Patent No. 1,23%,- 016, issued June 29, 1920, to.A..E. Lundell and F. A. Stearn. The operator controlling the district switch shown in Fig. 1 assigns the trunk shown in such figure, after receiving 'instructions from an A operator (not shown) "over an order wire not shown). The A operator then plugs into such trunk causing the operation of signals which inform the. cordless operator, as she will be termed hereafter, that a call is awaiting extension. The cordless operator then depresses an assignment key, whereupon the link circuit shown in Fig. 2 is put into operation. In practice there would be a number of, theselink circuits under the control of an allotter, but for the sake of simplicity only one link circuit has been shown. 7 The link circuit is provided at each end with a hunting switch. 'The cord finder at one end hunts for the district circuit at which the assignment key has been depressed, while the sender selector on the other end sender.

The cordless operator is provided with a setof office keysand with a set of numerical keys. The numerical keys correspond to those in the above mentioned patent to A. Lundell' and A. 'Stearn, No. 1,345,016 and are not shown inlthe present application toavoid needless duplication.

The operators oihce key set comprises two of suchlink, hunts for an idle rows of keys, there being one set of vertical signment key she will depress the proper oliice keys and the proper numerical keys. The multiposition switch shown in Fig. 7, which will hereafter be termed a translator switch, is then put'into operation to assumea position determined by the particular office keys depressed in the horizontal and the vertical rows. During the hunting movement of the translator switch, the reg ist/ration set upon the numerical keys is transferred to the sender register relays (not shown) ina'manner substantially, the

same as in the aforementioned Lundell- Stearn application.

After the tran l tor switch has been positioned an impulse generating machine comprising av plurality of drums which may be variably wired to the control circuit completed bythe translator switch brush, operates to energize theregister relays of Fig. 8 in variable combinations. The translator switch may then berestored and the registration is transferred from the relays in Fig. 8 to the sender register relays of Fig. 5.

After the registration has been set up on the relays of Fig. 5 the operation of the system is substantially similar to-that described in the previously mentioned Patent No. 1,345,016, to AJE. Lundell and F. A. Stearn.

The drums on the impulse generatin machine or impulser, as it may be terme are mounted on the same'shaft and are in continuous rotation. ln'order that a better understanding of the sequence of events during a rotation of the impulser may be had the face, the rectangles'and squares on thissurface representing points at which grounded battery or ground is supplied to any brush which is in engagement with such segment. The'direction of rotation of the drumsis assumed to be in the direction of the arrow as shown'in Fig. 6.

The mechanical construction of the transsection of the contact bank served by it.

Each brush is arranged to travel over a section of the bank comprising forty terminals.

A controlling commutator and associated commutator brushes are provided, this commutator being arranged w th s'egmentssuitably disposed to accomplish the control of the switch."

A detailed description of the operation of the system is as follows:

It willbe assumed that a subscriber at an outlying manual oflice wishes to originate a call. For the purpose of simplifying the description and drawings, it has been assumed that this call is to be extended to a localdesk. This means that no office selectors need be employed since the call is local and there will be noutility for numerical designation." The numerical keys and registersand their controllingcircuits have.

therefore been omitted.

n'th'e calling subscriber removes his recei'verfrom the switchhook, he will cause a signal to be lighted before anA operators position (not shown). erator will respond to this signal by plugging into the answering 1ack of the calling subscribers line and will then converse with him to ascertain the ofice and numerical designation of the call. The A operator will then converse with the cordless operator, one of whose circuits is shown in Fig. 1, by means of an order wire. The cordless operator will then assign a trunk and the A operator will plug into the outgoing end of such trunk. The substation of the calling subscriber and the A operators cord circuit together with the outgoing end of the trunk have not been disclosed. Suitable circuits for this purpose are, however, shown in Patent No. 1,342,823, issued June 8, 1920, toA. E. Lundell and E. H. Clarke.

As soon as the A operator has plugged into the trunk terminating in Fig. 1 in con ductors 101 and 102, a circuit is completed from grounded battery, sequence switch contact 103, right-hand winding of relay 104, conductor 101, through the cord circuit of the A operator and a supervisory relay included therein, returning by way of conductor 102, left-hand winding of relay 104, sequence switch contact 105 to ground. Relay 104 is energized in this circuit and completes a circuit from grounded battery, left-hand winding of relay 106, sequence switch contact 107, left hand armature and contact of relay 104 to ground. Relay 106 is energized in this circuit and completes a circuit from grounded battery through lamp 108, left-hand contacts of sequence switch spring 109, inner right-hand armature and front contact of relay 106, right-hand contact of sequence switch spring 110, outer right-hand armature and front contact of relay 106, lower contacts of sequence switch spring 111. to ground. The lamp 108 is lighted to inform the cordless operator that the A operator has plugged into the trunk jack. She thereupon depresses a non-locking assignment key 1.12, thereby completing a circuit from grounded battery, power magnet of sequence switch 100, lower right-hand contact of sequence switch spring 113. lefthand contacts of key 112, to ground, for moving this sequence switch out of position 1 and into position 2. As soon as sequence switch 100 leaves position 1, the circuit of relay 106 is opened and this relay deenergizes.

In position 2 of sequence switch 100, a

circuit is completed from grounded battery. winding of relay 201 (Fig. 2), left-hand contacts of sequence switch spring 202. conductor 203, upper left-hand and lower righthand contacts of sequence switch spring 114, inner right-hand armature and back contact of relay 106, upper contacts of sequence switch spring 109 to ground. Relay201is energized in this circuit and completes a The A opcircuit from grounded battery, left-hand 200, upper rigl1t-hand contact of sequence switch spring 206, inner right-hand armature and front contact of relay 204, to ground, for moving this sequence switch out of position 1 and intoposition 2. I y

In position 2 of sequence switch 200, a circuit is completed from grounded battery, winding of up-drive magnet 207, left-hand contacts of sequence switch spring 205, outer right-hand armature and front contact of relay'201 to ground. Under the control of magnet 207, the cord finder brush shaft is elevated in search of the terminal set corresponding to the district circuit at which the associated assignment key has been depressed. It is to be noted that as soon as sequence switch 200 leaves position 13;,relay 201 is maintained energized over a circuit extending through the lower contacts of sequence switch spring 202, the left-hand armature and back contact of relay 208, the upper right-hand and lower left-hand contacts of sequence switch spring 209 to ground, The test terminals associated with district switches, whose controlling sequence switches are in any other position than position 2,'are characterized by the absence of ground. Therefore test relay 208 does not become'energized until the cord finder test brush 210 engages test terminal 211, whereupon a circuit is completed from grounded battery, winding of relay 208, upper contact of sequence switch spring 212, test brush 210, test terminal 211, conductor 213, upper contacts of sequence switch spring 115, outer right-hand armature and back contact of relay 106, lower contacts of sequence switch spring 111 to ground. Relay 208is energized and at its left-hand armature opens the circuit of relay 201. Relay 201 remains energized for an instant longer due to a locking circuit extending from its inner right-hand armature and front contact, commutator 214, commutator brush 215 to ground.- When, an instant later, commutator brush 215 engages an insulating segment of commutator 214, at whichtime the cord finder brush set will be accurately centered on the selected terminal set, relay 201 is deenergized and opens at its outer right-hand armature the driving circuit of magnet 207. which deenergizes and allows thecord finder to come'torest. The deenergization of relay 201 completes a circuit from grounded hattery, power magnet of sequence switch 200,

201 to ground, for

moving this sequence switch out of position 2 and into position 3.

The operation of the sender selector shown at the right of Fig. 2 is simultaneous with the operation of the cord finder. It will be recalled that relay 204 was energized upon the initial energization of relay 201 to cause the advance of sequence switch 200 into position 2. hen sequence switch 200 leaves position 1%, the energizing circuit of relay 204 is interrupted at the right-hand contact of sequence switch spring 205, but if at this time the first sender is busy, which will be indicated by the fact that its controlling sequence switch 300 is in some position other than 1, a locking circuit is completed through the left-hand winding of relay 204, left-hand armature and front contact of relay 204, left-hand contacts of sequence switch spring 216, sender selector brush 217, which is engaging test terminal 218 of the set of terminals associated with the first sender, conductor 219, right-hand winding of relay 301, upper left-hand and lower right-hand contacts of sequence switch spring 302 to ground. With sequence switch 200 in position 2, a circuit is 00111- pleted from grounded battery, rip-drive magnet 220 of the sender selector, contacts of sequence switch spring 221, inner right-hand armature and front contact of, re-

lay 204 to ground. Magnet 220 isenergized in this circuit and causes the sender selector brush shaft to be moved upwardly in search of an idle sender. As soon as test brush 217 engages a test terminal 218 on which there is no ground potential, the locking circuit of. relay 204 is broker. Relay 204 is maintained energized a moment longer, however, due to the existence of a circuit extending from grounded battery, right hand winding of relay 204, lower left-hand and upper right-hand contacts of sequence switch spring 222, conducting segment of commutator 223, commutator brush224 to ground. When, a moment later, brush 224 engages an insulating segment of commutator 223, at which time the sender selector brush set will be accurately centered on the terminal set of an idle sender, the circuit through the right-hand winding of relay 204 is broken and this relay dcenergizes, causing in turn the deenergization of up-drivc magnet 220, thus bringing the sender selector to rest. It is to be observed that if the sender selector is the first to complete its operation the sequence switch 200 will remain in position until the cord finder has completed its operation, whereupon it will be moved into position 3. The deenergization of relay 204 then completes a circuit from grounded battery, power magnet of sequence switch 200, lower right-hand contact of sequence switch spring 206, inner right-hand armature and back contact of relay 204 to ground, for

its operation, the

winding of moving this sequence switchout 3 and into position 4.

If the cord finder is the first to complete sequence switch 200 will be advanced out of position 2 and into posi tion 3 as previously described. In position 3, the operation of the sender selector will continue as above described, since the circuits therein traced in each case function to the same purpose whether the sequence switch is in. position 2 or position 3 as may be readily ascertained by inspection of the drawing.

As soon as the sender circuit shown in Figs. 3, 4 and has been seized andth'e sequence switch 200 has reached position 4, a circuit is completed from grounded battery, left-hand winding of relay 301 (Fig. 3), upper right-hand and lower left-hand contacts of sequence switch spring 30", conductor 304, terminal 225, brush 226, righthand contacts of sequence switch spring 227, to ground. Relay 301 is energized in this of position circuit and locks up through its left-hand' armature and front contact to conductor 219 which is grounded by way of the upper lefthand and lower right-hand contacts of sequence switch spring 216. Ground potential is also supplied to test terminal 21.8 to render this sender non-selectable to other hunting sender selectors. Relay 301 upon energization also completes a. circuit from grounded battery, power magnet of sequence switch 300, lower left-hand contact of se quence switch spring 305, right-hand armature and front contact of relay 301 to ground, for moving this sequence switch out of position 1 and into position 6.

"With sequence switch 200 in position 4 and sequence switch 100 in position 2, a circuit is completed from grounded battery, right-hand winding of relay 204, left-hand contacts of sequence switch spring 222, inner right-hand armature and front contact of relay 228, which was energized when test relay 208 operated incident to the finding of the desired cord, cord finder brush 229, terminal 230, conductor 231, lower contact of sequence switch 116 to ground. Relay 204 is energized in this circuit and completes a circuit from grounded battery, power magnet of sequence switch 200,upper righthand contact of sequence switch spring 206, inner right-hand armature and front contact of relay 204, to ground for moving this sequence switch out of position 4 and into position 5.

As soon as sequence switch 200 reaches position 5, a circuit is completed from grounded battery, power magnet of sequence switch 100, conductor 117, lower contacts of sequence switch spring 118, conductors 119 and 120, terminal 232, brush 233, outer left-hand armature and front contact of relay 228, upper contact of sequence switch spring 234, to ground, for moving sequence switch 100 out of position 2 and'into position 3.

As soon as sequence switch 100 leaves position 2, the energizing circuit of relay 204 is broken and this relay deenergizes and. completes a circuit from grounded battery, power magnet of sequence switch 200, lower right-hand contact of sequence switch spring 206, inner right-hand armature and back contact of relay 204 to ground for moving this sequence switch out of position 5 and into-position 6.

As soon as sequence switch 100 reaches position 3, a circuit is completed from grounded battery, left-hand winding of re lay 106, lower right-hand contact of se quence switch spring 121, conductor 122,

lower contact of sequence switch spring 123,

to ground. Relay 106 is energized and completes a circuit from grounded battery, power magnet of sequence switch 100, conductor 117, left-hand contacts of sequence switch spring 12 1, inner right-hand armature and front contact of relay 106, upper contacts of sequence switch spring 109 to ground for moving this sequence switch out of position 3 and into position 5. As soon as sequence switch 100 leaves position 3 the energizing circuit of relay 106 is broken and this relay dcenergizes. The district sequence switch remains in position 5 until the fundamental circuit for controlling the selective operation of the switch is completed.

The operation of setting up the wanted number on the various registers will now be described. As previously mentioned, the operator is provided with a set of keys to control ofiice selection comprising a row of horizontal keys indicated generally at H in Fig. 7 and numbered from 1 to 10 and a row of twenty vertical keys shown generally at V, Fig. 7, and numbered from 1 to 20. She is also provided with a kei set provided with ten keys for each digit in the wanted number, these ten keys representing respectively the ordinate from 0 to 9. The numerical keys and the method in which they function to control registers will not be described.

The incoming call is to be diverted to the attention of an operator at a local desk. Assuming that the olfice code corresponding to a call which is to be routed to a local desk is AX, the cordless operator will immediately after depressing assignment key 112, as previously described, depress key No. 7 in the H'row and key No. 15 in the V row.

As soon as key A is depressed, a circuit is completed from grounded battery, winding of relay 701. Fig-8, upper contact of sequence switch spring 702, conductors 703 and 704:, right-hand contacts of key A,-con ductor 600to ground. Relay 701 is ener a locking circuit for itself through its right- 'lower right-hand contact of sequence switch spring707, left-hand armature and front contact of relay 701 to ground for moving this sequence switch out ofposition 1 and into position 2. Assoon as sequence switch 700 reaches position 1%, relay 701 completes hand armature and front contact and the left-hand armature and back contact of relay 708 to ground by way of the upper lefthand contact of sequence switch spring 709.

In position2 of sequence switch 700, brush selection is accomplished by the translatorswitch shown inFig. 7. Theoireuit of updrive magnet 601 extends .from grounded battery, winding of magnet 601 conductor 602, upper left-hand and lowerv right-hand contacts ofsequence switch spring 710, lefthand armature and front contact of relay 701 toground. It is to beobserved that with sequence switch 700 in position 2, relay 603,.Fig. 7, is energized over a .circuit'extending from grounded battery, winding of relay 603, conductor 604, left-hand contact of sequence switch spring 711 to ground.

During the upward movement of the translator brush shaft, commutator test brush 605successively engages the commutator segments in the right-hand group of the main commutator plate 606. The first five contacts to be engaged bybrush 605 are utilized to determine which brush shall be selected. Each brush serves a group of forty terminals. Thesefortyterminals are arranged in a continuous group. A special controlling circuit is used, the: operation of which will be subsequently described, so

that in case the desired terminal is in the lower twenty,v the selected brush will begin hunting starting from the lowermost. terminal in the lower twenty. In case,;however,.the desired terminal is in the .upper twenty, the selected brush will be moved over the contacts of the lower twenty without hunting in such group and will come to rest in engagement with'the lowermost terminal in the upper twenty. Thereafter it will be caused to hunt for the proper terminal. From this it is obvious that the selection of the desired one of two hundred terminals is accomplished, first, by selecting one of five brushes to select a group of forty terminals. Selection is then made to select an upper or. lower group of twenty terminals, after which the desired terminal is selected. The selection of a brush and the selection of a twenty group is made under the control of a key in the horizontal column. The selection of the particular contact in the twenty group is always under the control of a key in the vertical column.

The translator brush shaft is moved up keys when actuated.

'wardly as described until commutator brush tors 609 and 610, closed left-hand contacts of key A, conductor 611, lower right-hand contact ofsequence switch spring 709 to ground. Relay 708 is energized in this circuit and locks up to ground through its right-hand armature and the upper right-hand contact of sequence switch spring 709. Relay 708 at its left-hand armature opens the locking circuit of relay 701. Relay 701 is maintained energized a moment longer, however, due to the existence of a circuit extending by way of conductor 714:, a conducting segment of commutator 612, commutator brush 613 to ground. \Vhen, a moment later, commutator brush 613 engages an insulating segment of commutator 612, at which time the selected brush will be accurately positioned for tripping, relay 701 is deener gized and at its left-hand armature opens the circuit of up-drive magnet 601, causing the translator brush shaft to be brought to rest. The deenergization of relay 701 also completes a circuit from grounded battery,

power magnet of sequence switch 700, conductors 705 and 706, lower left-hand con tact of sequence switch spring 707, left-hand armature and back contact of relay 7 01 to ground, for moving this sequence switch out of position 2 and into position 8.

In position 3 of sequence switch 700, a circuit is completed from grounded battery, winding of trip magnet 614, conductor 615,

right-hand contact of sequence switch spring 711 to ground. Trip magnet 614 is energized and operates the trip rod controlled by it so that upon the subsequent upward movement of the translator switch shaft the second brush will be released into operative relation with the group of terminals served by it.

The keys numbered from 14) inclusive in the horizontal row are arranged to cause a selected brush set to hunt for a particular one of twenty terminals in the lower twenty of a selected group of forty terminals. This is accomplished due to the fact that ground is supplied to conductor 720 by way of the righthand contacts of such Any one of keys 6 to 10 in the horizontal row when actuated determine that hunting for the desired terminal set shall take place after the lower twenty group has been traversed. This is accomplished by supplying ground to con ductor 704: by way of the right-hand contacts of such keys. The manner in which this discrimination between twenty groups is accomplished will now be described.

Since key A has been depressed, which is one of the keys numbered 6 to '10 in the horizontal group, the desired terminal set is located in the upper twenty. Therefore, with sequence switch 700 in position 3, a circuit is completed from grounded battery, winding of relay 701, upper right-hand contact of sequence switch spring 702, conductors 703 and 1, closed right-hand contact of key A, conductor 600 to'ground. Relay 7 01' is energized in this circuit and locks up through its right-hand armature and front contact and the left-hand armature and back contact of relay 708, which was deenergized when sequence switch 700 left position 2, to ground by way of sequence switch spring 709. Relay 701 at its left-hand armature completes a circuit from grounded battery, power magnet sequence switch 700, lower right-hand contact of sequence switch spring 707, left-hand armature and front contact of relay 701 to ground for moving this sequence switch 'out of position 8 and into position 4:.

In position 4 of sequence switch 700, a circuit is completed from grounded battery, winding of up-drive magnet 601, conductor 602, upper left-hand and lower right-hand contacts of sequence switch spring 710', lefthand armature and front contact of relay 701 to ground. No test of the terminals in the commutator segment corresponding to the lower-most terminal set in the upper group of twenty, which is segment 618, a circuit is completed from grounded battery, winding of relay 708, right-hand contacts of sequence switch spring 712, conductor 7.13, brush 605, terminal 618, conductor 619, lower left-hand contact of sequence switch spring 715, conductor 704, closed right-hand contacts of the A .key, conductor 600to ground. Relay 708 is energized in this circuit and at its left-hand armature opens the locking circuit of relay 7 01. Relay 701' remains energized as previously described until the brush is accurately centered, whereupon it deenergizes and co-mpletes a circuit from grounded battery, power magnet of sequence switch 700, conductors 7 05 and 706, lower left-hand contact ofsequence switch spring 707, left-hand armature and back contact of relay 701, to ground, for moving this sequence switch out of position 4 and into position 5. Relay 708 is deenergized as soon as sequence switch 700 leaves position 4.

As soon as sequence switch 700 reaches position 5, a circuit is completed from grounded battery, winding of relay 701, conductor 716, contacts of sequence switch spring 717, conductor 718, closed right-hand contact ot key X, conductor 699 to ground. Relay 701 is energized and completes a cir: cuit for moving sequence switch 700 out of position 5 and into position 6, identical with the circuit traced for moving it from position 3 to position 4:. Relay 701 upon energization locks up through the left-hand armature and back contact of relay 708 as previously described.

In position 6 of sequence switch 700, the translator switch is moved upwardly in its final hunting movement, the circuit of updrive magnet 601 extending to ground at the left-hand armature and front contact of relay 701 over a path previously described.

When test brush 605 engages commutator segment 620, which is the segment in the upper twenty associated with key X, a circuit is completed from grounded battery,

winding of relay 708, contacts of sequence switch spring 712, conductor 713, brush 605, segment 620, conductor 621, closed left-hand contact of key X, conductor 622, upper right-hand contact of sequence switch'spring 719 to ground. Relay 708 is energized in this circuit-and opens at its left-hand armature the locking circuit of relay 701. When, a moment later, commutator brush 613 engages an insulating segment of commutator 612, relay 701 deenergizes and opens the circuit of up-drive magnet 601, allowing the translator brush shaft to come to rest with the second brush in engagement with the thirty-fifth terminal set in the group served by it. The horizontal keys determine the brush group, and also control the discrimination between the upper or lower half of a group of 40 terminals to be selected. The vertical keys determine the particular terminal in the selected subgroup of 20. Key No. 7in the H group determines, as shown, that one of the terminals in the second half of the group of 40 terminals is to be chosen, that is, a terminal between the 21st and 40th, inclusive, in that group. v The 15th key in the V group will determine that the 15th terminal of the second half of the 40 terminals is to be selected, that is, the 35th. Relay 701, upon deenergization, also completes a circuit from grounded battery, power magnet of sequence switch 700, conductors 705 and 706, lower left-handcontact of sequence switch spring 7 07, left-hand armature andback contact of relay 701 to ground for moving this sequence switch outof position 6 and intopositi'on 7. 3

As soon as the translator'switch ispositioned the first transfer of the ofiice, reg.- istration has been accomplished, since the position assumed by such translator switch determines what district and oflice selection are to be made. The method of transferring this registration from the translator switch to the register relays shown in Fig; 8,, by means of an impulse sending" device indicated generallyat 825, will now be .d'e' scribed. g

The impulse machine consists of a cylinder or drum mounted for rotation and constantly driven from any suitable sourceof power. The drum is divided into three sections, two of which are connected to grounded battery and one of which is connected to ground. In order to better portray the relative positions of the various conducting segments on the drum, the drum has been developed into a plane surface. The various rectangles and squares indicate conducting segments on the periphery of the drum.

It will be assumed that at the start of the setting operation the impulser' brushes occupy a position relative to the drum as indicated in Fig. 6. Direction of rotation of the drum is indicated by an arrow.

It will be assumed that translator brush 670! is in engagement with terminal 660 which is connected to conductor 661. Associated with impulse conductor 661 is a relay 800 fora purpose which will be apparent from the subsequent description. Assoeiated with each terminal of the translator switch isan impulse conductor and relay corresponding to conductor 661 and relay 800 respectively.

As soon as sequence switch 700 reaches position 7 a circuit is completed from grounded battery, winding of relay 721, upper contact of sequence switch spring 722 to ground. Relay 721 is energized and'attracts its armatures. A circuit is then completed from grounded battery, winding of relay 901, armature 751' and its front con tact, conductor 806, brush 832, segment 837 to ground. Relay 901 is energized in this circuit and extends the'circuit of relay 756 to impulse conductor '906'.

The in'ip'ulser rotate-s until brush 811 engages segment 816, atwhich time relay 7 56 is energized over a circuit extending from grounded battery; winding of relay 756, armature and front contact of relay 901, conductor 906, armature"7 54c and' its front contact, conductor 671, brush 670, terminal 660, conductor 661, armatureand back contact of relay 800, brush'811', segment 816 to ground. Relay 7 56 is energized and as soon as brush810 engages segnicnt818, a circuit is completed from ground, left hand windi-ng of relay 761, outermost armature and front contact of relay 756, conductor 763, brush810. segment 818; to grounded battery. Relay 761 is energized and locks up through its right hand winding and right hand armature and front contact to ground by way ofronductor 73 )"and the lower right hand contact of sequence switch spring 719. As. soon as brush"811fleaves segment 8 16, relay 756 is de-energized, but is again energized when brush 811 engages segment 901 is Clo-energized.

817. At this time the energization of relay 756 completes a circuit from ground, left hand winding of relay 766, innermost armature and front contact of relay 756, con ductor 767, brush 807, segment 819 to grounded battery. Relay 766 is energized and locks up to grounded conductor 739. When brush 832 leaves segment 837, relay As soon as brush 833 engages segment 838, relay 724 is energized over a circuit ere tending from grounded battery, winding of relay 724, conductor 902, armature 725, and its front contact, conductor 805, brush 833, segment 838 to ground. At the same instant that brush 833 engages segment 838, brush 814 establishes a connection to grounded battery by way of conducting segment 820. Therefore, as soon as brush 812 engages segment 821, a circuit is completed from ground, segment 821, brush 812, right hand winding of relay 800, brush 814, segment 820 to grounded battery. Relay 800 is energized in this circuit, and since relay 724 was previously energized, completes a circuit for relay 731 extending from grounded battery, winding of relay 731, armature and front contact of relay 724, conductor 906, armature 754 and its front contact, conductor 671, brush 670, terminal 660, conductor 661, armature and front contact of relay 800 to ground. With relay 731 energized,a circuit is completed for relay 732 as soon as brush 808 engages segment 823. This circuit extends from ground, left hand winding of relay 732, armature 735 andits front contact, conductor 736, brush 808, segment 823 to grounded battery. Relay 732 is energized and locked up to grounded conductor 739. As soon as brush 812 leaves segment 821, relay 800 is de energized, but is again energized when brush 812 engages segment 822 causing the energization of relay 731, as previously described. As soon as brush 810 engages segment 824, a circuit is completed from ground, left hand winding of relay 760, outermost armature and front contact of relay 731, conductor 763, brush 810, segment 824 to grounded battery. Relay 760 is energized and locked up as previously described. VVhen brush 812 leaves segment 822, relay 800 is de-energized, causing in turn the de-energization of relay 73].. When brush 833 leaves segment 838, relay 724 is de-energized. 7

When brush 834 engages segment 839, a circuit is completed from grounded battery, Winding of relay 7 28. Fig. 8, conductor 903,- armature 741, and its front contact, conductor 804, brush 834, segment 839 to ground. Relay 728 is energized and extends the impulse conductor to relay 7 30, thus placing relay 7 30 under the control of relay 800. As soon as brush 812 engages segment 825, ground is supplied to such brush and when brush. 814 engages segment 826,21 circuit is completed from grounded battery, segment 826, brush 814, right hand winding of relay 800, brush 812, segment 825 to ground. Relay 800 isenergized in this circuit, causing the energization of relay 7 30. As soon as brush 808 engagesseg ment 829, a circuit is completed from ground, left hand winding oflrelay 733,

armature 737 and its front contact, conductor 736,- brush 808, segment 829' to grounded battery. Relay 733 is energized and locked up over conductor 740 to ground at sequence switch spring 719. As soon as brush 814 leaves segment 826, relay 800 is tie-energized, causing in turnv the de-cnergization of relay 730. However, as soon as brush 814 engages segment 827, these'relays are again energized, and when brush 809 engages segment 830, a circuit is completed .of relay 7 30, conductor 763, brush 810, segment 831 to grounded.battery.. Relay 759 is energized and locked up. WVhen brush 814 leaves segment 828, relays 800, and 730 are de-energized. When brush 834 leaves, segment 839, relay 728 is de-energized. I I

As soon as brush 835 engages segment 840, a circuit is completed from grounded battery, winding of relay 742, conductor 904, armature 727, and its front contact, conductor 803, brush 835, segment 840 to ground. The resultant energization of';relay 742 extends the circuit of relay 749 to impulse conductor 906, thus placing relay 749 under the control of relay 800. As soon as brush 813 engages segment 843, a circuit is completed from grounded battery, segment 842, brush 815, left hand winding of relay 800, brush 813, segment 843 to ground. Relay 800 is energized in this circuit and causes in turn the energization of relay 749. Assoonas brush 809 engages segment .852, a circuit is completed from ground, left hand winding of relay 744, armature 748 and its front contact, conductor 747, brush 809, terminal 852 to grounded battery. Relay 744 is energized and locked up. .As soon as brush 813. leaves segment 843, relays 800'and 749 are de-energized, but are again energized when brush 81 3 engages segment; 844. At the same time, a circuit; is completed from ground, left hand winding of relay 758, armature, 764, and its front contact,

conductor 763, brush 810, segment 853- to grounded battery. Relay 758 is energized and locked up. When brush 813 leaves seg ment 844, relays 800 and 749 are de-energized. These relays are again energized as soon as brush 813 engages segment 845. Since immediately after this engagement takes place, brush 807 is brought into engagen'ient with segment 854, a circuit is completed from ground, left hand winding of relay 765, innermost armature and front contact of relay 749, conductor 767, brush 807, segment 854 to grounded battery. Relay 758 is energized and locks up to grounded conductor 740. As soon as brush 813 leaves segment 845, relays 800 and 749" are deenergized. V

\Vhen brush 836 engages segment 841 a circuit is completed from grounded battery, winding of relay 726, Fig. 8, conductor 905, armature 723 and its front contact, conductor 802, brush 836, segment 841 to ground. Relay 726 is energized and extends the circuit of relay 729 to impulse conductor 906,

thus placing relay 729 under the control of relay 800. As soon as brush 815 engages segment 847, relay 800 is energized by the completion of a circuit extending from.

grounded battery,'segment 847, brush 815, left hand winding of relay 800, brush 813, segment 846 to ground. The energization of relay 800'completes a circuit for ener gizing relay 7 29 as previously described. As

soon as brush 808 engages segment 856, with relay 729 energized, a circuit is completed from ground, left hand winding of relay 734, armature 738 and its front contact, conductor 7 36, brush 808, segment 856 to grounded battery. Relay 734 is energized and locks up to grounded conductor 739. As soon as brush 815 leaves segment 847 relays 800 and 729 are de-energized. These relays are again energized as soon-as brush 815 engages segment 848 by means of circuits identical with those previously traced. As soon as brush 809 engages segment 857 a circuit is completed from ground, left hand winding of relay 743, armature 746 and its .front contact, conductor 747, brush 809, segment 857 to grounded battery. Relay 743 is energized and locks up right hand armature. All of the register relays of Fig. 8 which are to be actuated have now been energized and locked up.

Before continuing further with the description of the operation of the system,.it might be well to note that the impulser, by controlling relays 901, 724, 728, 742 and 726 by means of segments 837 to 841 inclusive operates these relays as a distributor switch to distribute the impulses which are sent over impulse conductor 661. It will also be noted that each of the four connections .to the windings of relay 800 may be used at the proper time to control the selecthrough its inner tive registers. This constitutes a novel arrangement in 'the transmission of impulses from an impulse generating device.

Brush 849 co-operates with segments 850 and 851 to control the counting relays which in turn control the advance of sequence switch 700 out of position 7 in order to ensure that this sequence switch will not be advanced until the impulser has made a complete revolution. This ensures that all of the register relays will have been actuated. As soon as brush 849-engages segment 850, a

circuit is completedfrom groundedbattery,

segment 850, brush 849, conductor 67 7, inner right hand armature and front contact of relay 721 winding of relay 771 to ground. Relay 771 is energized and completes a circuit from grounded battery, winding of re lay 768, armature and back contact of relay 769, armature and front contact of relay 771 to ground. Relay 768 is energizedand prepares a circuit for relay 769 by way of the armature and front contact of relay 768. As soon as brush 849 leaves segment 850 relay 771 is (lo-energized and thus removes the shunt from about the winding of relay 769 which becomes energized. The counting relays are operated in the well known manner and after the completion of the third impulse over conductor 677, which occurs soon as brush 849 leaves conductor 850 for the second time, relay 770 is energized.

Regardless of the position of the impulse generating device at the time the registering operation is begun, it is obvious that a trifle more than a complete revolution of the impulser is necessary before relay 770 can be energized. The energization of relay 770 completes a circuit. from grounded battery, power magnet of sequence switch 7 00, lower left hand contact of sequence switch spring 772, right hand armature and front contact of relay 770 to ground, for moving this sequence switch out of position 7 and into position 8.

As soon as sequence switch-700 leaves position 7, relay 721 is de-energized and completes a circuit from grounded battery, winding of down drive magnet-679, conductor 680, outer right hand armature and back contact of relay 721, lower contact of sequence switch spring 722 to ground. The translator switch is returned to its normal position under the control of magnet 679 and when the translator brush shaft reaches its are depressed a diflerent setting of the translator switch is accomplished under the joint control of the horizontal and vertical keys, as previously described. Another conductor, corresponding to 661 and connected to a relay corresponding to relay 800 as shown in Fig. 6, will be used. The relays in Fig. 8 are then operated as circuits are closed when corresponding brushes make contact with segments on the impulse machine in a manner similar to that just described.

The operation of transferring the registration from the relays of Fig. 8 to the relays of Fig. 5 will now be described.

lVhen sequence switch 7 00 reaches position 7%,- a circuit is completed from grounded battery, right hand winding of relay 502 (Fig. 5), conductor 503, lower contacts of sequence switch spring 308, closed due to the fact that sequence switch 300 is in position 6, conductors 309, 310 and 311, terminal 240 brush 241, conductors 242 and 243, upper left hand and lower right hand contacts of sequence switch spring 244, conductor 245, upper right hand contact of sequence switch spring 774, left hand armature and front contact of relay 734 to ground. i

Relay 502 isenergized in this circuit and locks up through its left hand armature to conductor 504, which is grounded at the upper right-hand contact of sequence switch spring 312.

When sequence switch 700 reaches position 8, a circuit is completed from grounded battery, right hand winding of relay 500 .(Fig. 5), conductor 501, upper contacts of sequence switch spring 306, which are closed due to the fact that sequence switch 300 is in position 6, conductor 307, terminal 235, brush 236, conductor 237, lower contact of sequence switch spring 238, conductor 239, upper right hand contact of sequence switch spring 775, through the outer right hand armatures and front contacts of relays 743 and 734 in parallel, conductor 776, right hand and left hand windings of relay 777 in series, upperarmature and back contact of relay 778 to ground. Relay 777 is energized in thiscircuit but marginal relay 500 is not energized, due tov the fact that the high resistance winding of relay 777 was included in this circuit. Relay 7 77 upon energization locks up through its inner left hand armature and front contact and in so doing removes the shuntrfrom about the winding of relay 778, allowing this relay to be energized due to the completion of a circuit extending from grounded battery, resistance 7'79, upper left hand contact of sequence switch spring'780, winding of relay 778 to ground. This last mentioned circuit was previously in existance, but relay 778 was shunted by the presence of direct ground supplied by way of the lower armature and hack contact of relay 778 and the inner left hand armature and back contact of relay 7 77 With sequence switch 700 in position 8, a circuit is also completed from ground, right hand winding of relay 505, conductor 506, upper contacts of sequence switch spring 313, conductor 314, terminal 246, brush 247, lower contact of sequence switch spring 248, conductor 249, lower contact of sequence switch spring 781, left hand armature and front contact of relay 743, resistance 782 to grounded battery. Relay 505 is energized in this circuit and locks up through its left hand winding and left hand armature and front contact to grounded conductor 504.

As soon as relay 7 7 7 is energized, a circuit is completed from ground, winding of relay 315 (Fig. 3), upper contact of sequence switch spring 316, conductor 321, right hand winding of marginal relay 507 conductors 508 and 322, terminal 250, brush 251, conductor 252, upper right hand cont-act of sequence switch spring 783, conductor 784, high resistance 785, conductor 786, outer left hand armature and front contact of relay 7 7 7, low resistance 787 to grounded battery. Relay 315 is energized in this circuit but relay 507, being marginal, does not become energized due to the inclusion in its circuit of high resistance 785. The energization of relay 315 completes a' circuit from grounded battery, power magnet of sequence switch 300, armature and front contact of relay 315, lower left hand and upper right hand contacts of sequence switch spring 317, armature and back contact of relay 3:18 to ground for moving this sequence switch out of position 6 and into position 7.

As soon as sequence switch 300 leaves position 6, the energizing circuit for relay 7 77 is opened and this relay de-energizes, completing a circuit from grounded battery, power magnet of sequence switch 700, upper right-hand contact of sequence switch spring 788, left hand armature and back contact of relay 789, lower armature and front contact of relay 77 8, inner left hand armature and back contact of relay 777 to ground, for moving this sequence switch out of position 8 and into position .9. As soon as sequence switch 7 00 leaves position 8, the circuit of relay 778 is broken at'sequence switch spring 780 and this relay'de-energizes.

In positions 9 and 7 of sequence switches 700 and 300 respectively, the setting of the re isters in Fig. 5 is continued. This operation is as follows. i

When sequence switch. 700 reaches position 8 3;- a circuit is completed from ground, right hand winding of relay 509,-right hand winding of marginal relay 510, conductor 511, contacts of sequence switch spring 323, conductor 307, terminal 235, brush 236, conductor 237, lower contact of sequence switch spring 238, conductor 239, upper left hand contact of sequence switch spring 775, left hand armature and front contact of relay 7 65, low resistance 782, to grounded battery. Since only a low resistance is included in this circuit, both relays 509 and 510 are energized in spite of the fact that relay 510 is marginal. These relays upon energization lock up to grounded conductor 504. At the same time a circuit is completed from ground, right hand winding of'relay; 512, right hand winding of marginal relay 513, conductor 514, lowercontacts of sequence switch spring 325, conductor 322, terminal 250, brush 251, conductor 252, lower left hand contact of sequence switch spring 790, left hand armature and front contact of relay 732, high resistance 791, low resistance 792 to ground. Due to the presence ofthe high resistance 791 in this circuit, relay 513 which is marginal, does not become energized. Relay 512 does, however, become energized and locks up through its left hand winding.

When sequence switch 7 reaches position 9, a circuit is completed from grounded battery, left hand winding of marginal relay 515, conduct0r'516, lower contacts of sequence switch spring 324, .conductor 314, terminal 246, brush 247 contact of sequence switch spring 248, conductor 249, upper right hand contact of sequence switch spring 7 81, outer right hand armature and front contact of relay 732, outer right hand armature and front contact of relay 765, conductor 793, high and low resistance windings of relay 789 in series to ground through the outer armature and back contact of relay- 794. At the same time a parallel path is closed extending through the left hand armature and front contact of relay 744, upper contact of sequence switch spring 795, conductor 796, low resistance right hand winding of relay 789 and thence to ground; Relay 789 is energized in this circuit and due to the fact that the last traced parallel path short-circuits the high resistance right hand winding of relay 789, inarginal relay 515 (Fig. is allowed to energize. Relay 515 upon energization locksup to grounded conductor 504. Relay 789, upon energization locks up through its inner right hand armature and front contact and at the same time removes the shunting ground which spring 320, conductor 326, left hand winding of marginal relay 517, conductors 518,

786, outer right hand armature and front contact of relay 789, low resistance 787 to grounded battery. Due to the presence of the high resistance 785, relay 517 cannot become'energized. Relay 318 does, however, become energized and completes a circuit from grounded battery, power magnet of sequenceswitch 300,armature and back contact of relay 315, upper left hand and lower right hand contacts of sequence switch spring 317, armature and front contact of relay 318, to ground for moving this sequence switch out of position 7 and into position 8. I

As soon as sequence switch 300 leaves'position 7, relays 318 and 789 are de-energized. The de-energization of relay 789 completes a circuit from grounded battery, power.

magnet of sequence switch 700, upper left 'through the high resistance 785, conductor hand contact of sequence switch spring 788,

right hand armature and back contact of relay 777, lower armature and front contact of relay 7 94, inner right hand armature and back contact of relay 7 89 to ground for moving this sequence switch out of position 9 and into position 10. As soon as sequence switch 700 leaves position 9, the-holding circuit of relay 794 is broken and this relay de-energizes.

When sequence switch 700 reaches position 9%, a circuit is completed from ground, right hand winding of relay 519, right hand winding of marginal relay 520, conductor 521., right handcontact of sequence switch spring 327, left hand contact of sequence switch spring 313, conductor 314, terminal 246, 7 brush 247, contact of sequence switch spring 248, conductor 249, upper left hand contact of sequence switch spring 781, left hand armature and front contact: of relay 733, high resistance 797, low resistance 782 'to grounded battery. 'Due to the presence of high resistance 797 in this circuit, relay 520 does not become energized. Relay 519 does, however, become energized and locks up to grounded conductor 504.

hen sequence switch 700 reaches position 10, a circuit is completed from grounded battery, left hand winding of marginal relay 522, conductor 523', upper contact of sequence switch spring 328, left hand contact of sequence switch spring 306, conductor 307, terminal 235, brush 236, conductor 2 37, contact of sequence switch spring 238, conductor 239,1ower left hand contact of sequence switch spring 7 7 5, outer right hand armature and front cont-act of relay 733,

conductors 798 and 776, high and low resistance windings of relay 77 7 upper armature and back contact of relay 778 to ground.

The high resistance right-hand winding of relay 777 is however, shunted by a path eX- tending from the lower left-hand contact of sequence switch spring 775, left-hand armature and front contact ofrelay 745, lower right-hand contact of sequence spring 866,

' conductor ;867 to the low resistance left'hand relay 524, conductors 508 and 322, terminal 250, brush 251, conductor 252, upper right hand contact of sequence switch 783, conductor 784, high resistance 785, conductor 786, outer left hand armature and front contact of relay 777, low resistance 787 to grounded battery. Relay 315 is energized in this circuit, but relay 524 cannot become energized due to the presence of high resistance 785. There is in addition, however, a circuit extending from conductor 252 by way of the upper left hand contact of sequence switch spring 790, left hand armature and front contact of relay 759, and thence by way of conductor 799 to conductor 786 and to grounded battery as previously described, It is to be observed that this last traced circuit short circuits the high resistance 785 and renders it ineffective. Therefore, relay 524 is energized and locks up through its left hand armature.

The energization offrelay 315 completes a circuit from grounded battery, power magnet of sequence switch 300, armature and front contact of relay 315, lower left hand and upper right hand contacts of sequence switch spring 317, armature and back con 10 and into position 11. As soon as sequence switch 700 leaves position 10, relay 778 is de-energized. WVhen sequence switch 7 00 reaches position 10% a circuit is completed from ground, right hand winding of relay 527, right hand winding of marginal relay 528, conductor 529, lower contact of sequence switch spring 328, upper contact'of sequence switch spring 306, conductor 307, terminal 235, brush 236, conductor 237, contact of sequence switch spring 238, conductor 239, lower right hand contactof sequence switch spring 77 5, left hand armature and front contact of relay 766, low resistance 782 to grounded battery. Since only a low resistance is included in this circuit, relays 527 and 528 are both energized and lock up through their left hand windings. 'At the same time a circuit is completed from grounded battery, winding of relay 530, conductor 531, left hand contacts of sequence switch spring 325, conductor 322, terminal 250, brush 251, conductor 252, left hand contact of sequence switch spring 783, left hand armature and front contact of relay 760 to ground. Relay 530 is energized in this cirwit and locks up through its left hand armature and front contact to grounded conductor 504.

When sequence switch 700 reaches position 11, a circuit is completed from grounded battery, left hand winding of marginal relay 525, conductor 526, left hand contact of sequence switch spring 327, left hand contact of sequence switch spring 313, conductor 314, terminal 246, brush 247, contact of sequence switch spring 248, conductor 249, lower left-hand contact of sequence switch spring 781,. outer right hand armature and front contact of relay 766, conductor 793, highand low resistance windings of relay 789 in series, upper armature and back contact of relay 794 to ground. Relay 789 is energized in this circuit, but due to the fact that the high resistance left hand winding of relay 789 was included in this circuit, marginal relay 525 does not become energized. Relay 789 upon energization locks up through its inner right hand armature and front contact and in doingrso removes the shunt from about the Winding of relay 794,. which relay therefore becomes energizedr The energization of relay 7 89 completes a circuit from ground, winding of relay 318 (Fig. 3), upper contacts of sequence switch spring 319, conductor 330, right hand winding of marginal relay 532, conductors 518, 310'and 311, terminal 240 brush 241, conductors 242 and 243, upper left hand and lowerright hand contacts of sequence switch spring 244, conductor 245, upper left hand contact of sequence switch spring 774, high resistance 785, conductor 7 86, outer right hand armature and front 

